Experiment 24
Name: ________________________
The Greenhouse Effect
Greenhouses allow gardeners to grow plants in cold weather. This is because the air inside the
greenhouse stays warmer than the outside air. Short wavelength radiation from the sun passes
through the glass. It is then absorbed by plants and other materials in the greenhouse and converted
to long wave radiation (infrared), warming the interior of the greenhouse. The longer-wavelength
radiation does not pass through glass and is trapped in the greenhouse. This, along with the lack of
mixing between the inside and outside air, keeps the greenhouse warm.
Reflected Back to Space
Incoming Solar
Radiation
Re-radiated
Back to
Surface
Reaches Surface
Absorbed by
Greenhouse
Gases
Heat Radiated
Back from Surface
On a larger scale, the
greenhouse effect helps keep
our planet warm. Figure 1
shows how short wavelength
radiation from the sun passes
through the atmosphere,
warming the Earth. The
longer wavelength energy is
then trapped by certain gases
called greenhouse gases.
Greenhouse gases most
responsible are water vapor,
carbon dioxide, methane, and
nitrous oxide.
Atmosphere
In this experiment, you
will use two Temperature
Probes to measure and
Figure 1
compare the temperatures in
model greenhouses under various conditions. In Part I, you will investigate the role of a plastic
covering over the top of the model greenhouse. In Part II, you will investigate the effect of increased
levels of two greenhouse gases – water vapor, H2O, and carbon dioxide, CO2.
OBJECTIVES
In this experiment, you will


Use Temperature Probes to measure temperatures in a model greenhouse and a control.
Use the results to make conclusions about the greenhouse effect.
MATERIALS
Computer
Vernier computer interface
Logger Pro
2 Temperature Probes
lamp with 100 watt bulb
plastic wrap
sand
2 rulers
Tape
two 600 mL beakers
PROCEDURE
Part I The Effect of a Plastic Cover
1. Plug the Temperature Probes into Channels 1 and 2 of your Vernier computer interface.
Earth Science with Computers
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Experiment 24
2. Rubber band Probe 1 and Probe 2 each to a ruler as shown in
Figure 2. The probe tips should each be 3 cm from the ruler
ends and the bands should not cover the probe tips.
3. Open the LoggerPro program and prepare the computer for
data collection by opening the file “24 Greenhouse Effect”
from the Earth Science with Computers folder.
4. Obtain two beakers and prepare them for data collection.
Figure 2
a. Place a layer of sand 1 cm deep in each beaker.
b. Place the Temperature Probes into the beakers as shown in Figure 2.
c. Cover the top of Beaker 1 (the beaker containing Probe 1) tightly with plastic wrap. There
should not be too much excess plastic wrap covering the sides of the beaker. Beaker 1 is your
covered greenhouse and Beaker 2 is the control.
d. Position a lamp bulb the same distance from both beakers. The bulb should be about 15 cm
above the tabletop and the same distance from the two probe tips.
5. Click
to begin data collection. Turn on the lamp.
6. Monitor the time in the meter. When 5 minutes have passed, turn off the lamp. Data will
continue to be collected.
7. At the 10 minute mark, turn the lamp back on. Data collection will stop after 15 minutes.
8. When data collection stops, turn the lamp off.
9. Turn on the Examine feature by clicking on the Examine button,
, on the toolbar.
10. Move the cursor to the 0 minute mark on the graph. Use the Examine box to determine the
temperatures in Beaker 1 and Beaker 2 and record them in your data table.
11. Use the same method to determine the temperatures at the 5, 10, and 15 minute marks and record
them in your data table.
12. Print copies of the graph as directed by your teacher.
13. Choose Store Latest Run from the Experiment menu.
Part II The Effect of Greenhouse Gases
14. Cover Beaker 2 tightly with plastic wrap. The ruler and probe should still be in place.
15. Lift the edge of the plastic wrap on Beaker 1 to make an opening.
16. Take a deep breath and hold it for as long as is comfortable. Without touching your lips to the
beaker, exhale into the opening filling Beaker 1 with your breath.
17. Reseal the plastic over the top of the beaker and reposition near the lamp. Make sure the beakers
are the same distance from the lamp and are being illuminated evenly as in Part I.
18. Click
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to begin data collection. Turn on the lamp.
Earth Science with Computers
The Greenhouse Effect
19. Monitor the time in the meter. When 5 minutes have passed, turn off the lamp. Data will
continue to be collected.
20. At the 10 minute mark, turn the lamp back on. Data collection will stop after 15 minutes.
21. When data collection stops, turn the lamp off.
22. Turn on the Examine feature by clicking on the Examine button,
, on the toolbar.
23. Record the temperature values at the 0, 5, 10, and 15 minute marks in your data table.
Important: Be sure that you are reading the “Latest” temperature values and not the Run 1
values from the Examine box.
24. Print copies of the graph as directed by your teacher.
DATA
Part I The Effect of a Plastic Cover
Probe 1
Greenhouse
Probe 2
Control
Temperature
Difference
Probe 2
Control
Temperature
Difference
0 Minute Temperature (°C)
5 Minute Temperature (°C)
10 Minute Temperature (°C)
15 Minute Temperature (°C)
Part II The Effect of Greenhouse Gases
Probe 1
Greenhouse Gases
0 Minute Temperature (°C)
5 Minute Temperature (°C)
10 Minute Temperature (°C)
15 Minute Temperature (°C)
PROCESSING THE DATA
Part I The Effect of a Plastic Cover
1. In the spaces provided in your data table, subtract to find the temperature differences.
2. During periods when the lamp was on, did the covered beaker warm faster or slower than the
control? Give a possible explanation for your answer.
Earth Science with Computers
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Experiment 24
3. During periods when the lamp was off, did the covered beaker cool faster or slower than the
control? Give a possible explanation for your answer.
4. Explain why a closed automobile heats up in the sun.
Part II The Effect of Greenhouse Gases
5. In the spaces provided in your data table, subtract to find the temperature differences.
6. What two important greenhouse gases did the exhaled air contain?
7. During periods when the lamp was on, did the beaker with greenhouse gases warm faster or
slower than the control? Give a possible explanation for your answer.
8. During periods when the lamp was off, did the covered beaker warm faster or slower than the
control? Give a possible explanation for your answer.
9. In what way is the greenhouse effect good for the Earth?
10. In what ways might the greenhouse effect become a problem for the Earth?
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Earth Science with Computers